avr/main.c

   1 /* Z80 Mainboard Controller */
   2
   3 #include <stdio.h>
   4
   5 #include <avr/io.h>
   6 #include <avr/interrupt.h>
   7 #include <avr/pgmspace.h>
   8 #include <util/delay.h>
   9
  10 #include "uart.h"
  11 #include "bus.h"
  12 #include "i2c.h"
  13 #include "mem.h"
  14 #include "io.h"
  15
  16 #include "monitor.h"
  17
  18 uint8_t xorshift(uint8_t new_seed)
  19 {
  20         static uint8_t seed = 0xA5;
  21         if(new_seed) seed=new_seed;
  22
  23         seed ^= (seed << 1);
  24         seed ^= (seed >> 1);
  25         seed ^= (seed << 2);
  26         return(seed);
  27 }
  28
  29 int main(void)
  30 {
  31         /* initialize serial port and stdin/stdout */
  32         uart_init();
  33         stdout = &uart_out;
  34         stdin  = &uart_in;
  35         sei();
  36
  37         /* initialize hardware and monitor */
  38         printf_P(PSTR("\nAVR INIT "));
  39         printf_P(PSTR("[BUS")); bus_init(); printf_P(PSTR("] "));
  40         printf_P(PSTR("[I2C")); i2c_init(); printf_P(PSTR("] "));
  41         printf_P(PSTR("[MEM")); mem_init(); printf_P(PSTR("] "));
  42         printf_P(PSTR("[I/O"));  io_init(); printf_P(PSTR("] "));
  43         printf_P(PSTR("[MON] ")); monitor_init();
  44         printf_P(PSTR("DONE.\nSend BREAK to enter monitor.\n"));
  45
  46         /* load initial program into memory */
  47         menu_ihex();
  48
  49 #if 0
  50         mem_start();
  51         for(uint8_t i = 0; i < 8; i++) printf("%02x ", mem_read(i));
  52         mem_stop();
  53 #endif
  54
  55         /* reset Z80 */
  56         printf_P(PSTR("Go!\n"));
  57         bus_reset();
  58         bus_unlock();
  59         bus_wait();
  60
  61         while(1) {
  62                 if(!(MEMPIN & (1 << SEL))) {    /* got I/O request */
  63
  64                         /* answer the I/O request */
  65                         if(!(MEMPIN & (1 << RD))) {
  66 //                              printf_P(PSTR("<IORD>"));
  67                                 io_read();
  68                         } else if(!(MEMPIN & (1 << WR))) {
  69 //                              printf_P(PSTR("<IOWR>"));
  70                                 io_write();
  71                         } else {
  72                                 printf_P(PSTR("<IOFAIL>"));
  73                                 while(1);
  74                         }
  75
  76                         while(!(MEMPIN & (1 << SEL)));
  77                 }
  78
  79                 if(uart_break) monitor();       /* enter monitor on break */
  80         }
  81
  82         printf_P(PSTR("\nAVR END\n"));
  83         while(1);
  84 }